Far from infallible, expert comparisons of hair, handwriting, marks made by firearms on bullets, and patterns such as bite marks and shoe and tire prints are in some ways unscientific and subject to human bias, a National Academy of Sciences panel chartered by Congress found. Other techniques, such as in bullet-lead analysis and arson investigation, survived for decades despite poorly regulated practices and a lack of scientific method. Even fingerprint identification is partly a subjective exercise that lacks research into the role of unconscious bias or even its error rate, the panel’s 328-page report said.